Air squeegee



y 1965 E. R. TOWNLEY ETAL 3,

AIR SQUEEGEE Filed March 13, 1964 5 4 FIG] I /5 FIG-.3

United States Patent 3,195,163 AIR SQUEEGEE Eustace Raymond Townley andEric Alfred Harvey, Ilford, Essex, and Howard Thomas Tillotson, London,England, assignors to lilford Limited, lltord, Essex, England, a Britishcompany Filed Mar. 13, 164, Ser. No. 351,649 Claims priority,application Great Britain, Mar. Ztl, 1963, 11,089/63 9 Claims. (Cl.153ll6) The present invention relates to an apparatus for the removal ofsurface moisture from a wet travelling web.

According to the invention there is provided an apparatus for removingliquid from the surface of a wet travelling web which comprises achamber through which the web is constrained to pass, inlet and outletpassages for the web at least one being constituted by the narrow gapbetween a pair of oppositely curved surfaces, the generating lines ofwhich are parallel to the width of the web, one of said surfaces beingfixed and the other being a surface of a floating member which is somounted as to allow it a small degree of freedom of movement in a senseallowing variation of the thickness of the gap but limited in suchmovement so that the gap cannot be wholly closed thereby, means forintroducing a current of air into said chamber so as to urge saidfloating member towards its co-operating curved surface and providing apath for such air to impinge on both faces of the web, and means wherebyany increase in the thickness of a said gap beyond a predetermined valueby reason of movement of the said floating member from a pre-setposition causes an increase in the air pressure on said member tendingto restore it to its pre-set position.

A particular use for an apparatus of this type is as an air squeegee forthe rapid removal of surface water from a web of photographic filmduring processing. When a length of film is being processed in a normalcontinuous processing machine it is essential to remove excess surfacemoisture before the film enters the dryer. Further, when a length offilm is being processed in a so-called rapid processor wherein theprocessing solutions are either sprayed or coated onto the film and thenwashed off, it may be essential to remove excess moisture after eachwater wash and before the next processing solution is applied, or beforedrying. In the past this has been carried out using squeegee rollers,air knives or air squeegees. Squeegee rollers are inclined to scratchthe film surface and the air Squeegees and air knives hitherto producedhave used too much air.

A film web for processing usually consists of lengths of film joinedtogether or spliced. These splices may be more than twice the thicknessof the normal film and so an air squeegee must be designed to enablesplices to be passed easily through it and also to ensure that the widergap caused by the passage of the splice should be quickly closed to itsnormal size to avoid the escape of too much air through this gap.

A particular embodiment of the invention has as its pair of curvedsurfaces a pair of cylinders of which one is fixed and the other free tomove to a restricted extent. The cylinders can be prevented from whollyclosing by providing either the fixed or the floating cylinder withflanges. In a preferred embodiment of the invention the fixed cylinderhas flanges.

In order to ensure that after a splice has been passed through theapparatus the floating member returns to its pre-set position, thepreferred apparatus is so constructed that when the floating member hasbeen displaced it acts to divert the air supply to cause it to re-setthe floating member in its working position.

In one preferred form of the invention, the cylinder ice used as thefloating member is arranged to have restricted movement in a parallelsided recess formed in the body of the apparatus. When the cylinder isat the open end or" the recess it abuts the flanges of the fixedcylinder and when it is moved towards the closed end of the recess itacts to restrict the air passage to the central air chamber so causingan increased air pressure on its undersurface which forces it back tothe position in which it abuts the flanges of the fixed cylinder. Thepreferred embodiment of the invention for use as an air squeegee duringthe processing of photographic film comprises a pair of oppositelycurved surfaces at each of the inlet and outlet passages.

In order that the invention may be readily understood the preferredembodiment of the invention will now be described with reference to theaccompanying drawings in which- FIG. 1 is an elevation of an airsqueegee.

FIG. 2 is a plan view of the squeegee with an end plate removed to showthe internal arrangement and to indicate by means of dotted lines theposition of channels below the plane surface of the figure.

PEG. 3 shows two cylinders removed from the squeegee to illustrate theirshape and shows how the floating cylinder abuts the flanges of the fixedcylinder.

Referring to the figures: FIG. 1 shows an elevation of an air squeegeewherein '7 and 8 are two halves of the squeegee which contain inrecesses the cylinders 1 and 2 and which are held together by the endplates 5. Two pins 4 are held in recesses in the blocks 7 and 8 and determine the path of a film by preventing it rubbing against the endplates 5. An air inlet pipe 6 is attached to block 8. The gap betweenthe cylinders l and 2 which is formed by cylinder 2 resting on theflanged ends of cylinder 1 is designated at 3. It is through this gapthat the film is threaded and out of which the air is forced.

FIG. 2 which is a plan view of the apparatus with the end plates 5removed shows how cylinders l are con tained in recesses in block 7 andare locked in place by' rubber sealing strips 9. Cylinders 2 are mountedin recesses it) in block 8 but are free to move in these recesses. Theyare normally held against the flanged ends of the cylinders l, as shownin the figure, by air pressure. The ends of the pins 4 are contained inrecesses in the blocks 7 and 8. An air inlet pipe 6 is attached toblocks 8. The gap into which the film 14 is threaded is designated at11.

The dotted lines on the surface show the air channel which is below thesurface of the plane of the figure.

These channels enable air to be fed from the air inlet 6' to thecylinder recesses 19. The portion of cylinder block 8 between thecylinder recesses 10 is designated at 12. This is cut away below thesurface to enable air from the cylinder recesses ill to be fed into themain air chamber 13.

FIG. 3 shows the cylinders 1 and 2 removed from their recesses toillustrate their shape and show how cylinder 2 rests on the flanged ends15 of cylinder 1. The ends of cylinders 2 are rounded off to preventthem jamming against the end plates 5.

When in use air from the inlet 6 enters the cylinder recesses ltlforcing the cylinders 2 to rest on the flanges 15 of cylinders 1. Airalso passes from recesses It) into the channel under 12 to the main airchamber 13. As can be seen from FIG. 1 the length of the air chamber 13is longer than the width of a film threaded into gap 3 by at least thewidth of the pins 4. This gap either side of a film traveling throughthe apparatus enables air to be forced to the back of the film. The airis then forced out of the apparatus via the two gaps on either side ofthe film so preventing the film ever touching either of the two pairs ofcylinders.

When a length of film is joined to another length a splice which may bemore than twice the normal thickness of the film is formed. When aspliced portion of film enters the apparatus the extra thickness of thefilm causes at first one of the cylinders Z to go back into its recessand then the other one. passed and film of a normal thickness is passingthrough the apparatus the air forces back the cylinders 2 onto theflanges of cylinders 1. Excess air pressure to do this is not requiredbecause when the cylinders 2 are forced back into the recesses 10 theyrestrict the air passage into the main air chamber 13 via the channelunderportion 12 and therefore all the air is used to force back thecylinders 2 onto cylinders 1. This reopens the passage to chamber 13.

An air squeegee of this type ensures very good squeegeeingcharacteristics by making use of a very small air gap between thecylinders but still ensuring that the film in the normal way nevertouches the cylinders. A squeegee of this type is able to pass slicesvery easily and the cylinders return straight away to their normalposition without excessive air pressure having to be used. A squeegeeWhen the splice has of this type may be used in any position or at anyangle as the movable cylinder is returned to its original position byaid pressure and not by any reliance on gravity.

It is an advantage of the present invention that excess air pressure isnot required to move the cylinders 2. (as noted above). This is ofimportance because it will be appreciated that when a number of airSqueegees are used on an air supply of limited capacity, increase in airconsumption caused by the multiplicity of units would drop the pressureto all theunits, and thus cause relative inefficiency.

We claim as our invention.

1. An apparatus for removing liquid from the surface of a wet travellingweb which comprises a chamber through which the web is constained topass, inlet and outlet passages for the web at least one beingconstituted by the narrow gap between a pair of oppositely curvedsurfaces, the generating lines of which are parallel to the width of theweb, one of the sa'id'surfaces being fixed and'the other being a surfaceof a floating member which is somounted as to-allow it a small degree offreedom of movement in a sense allowing variation of the thickness ofthe gap but limited in such movement so that gap cannot be wholly closedthereby, means for introducing a current of air into said chamber so asto urge said float.- ing member towards its cooperating curved surfaceand providing a path for such air to impinge on both faces of the web,and means whereby any increase in the thickness of the said gap beyond apredetermined value by reason of movement of the said floating memberfrom a pre-set position causes an increase in the air pressure on saidmember tending to restore it to its pre-set position.

2. An apparatus according to claim 1 which has as its pair of oppositelycurved surfaces a pair of cylinders one of which is fixed and the otherof which is floating.

- 3. An apparatus according to claim 1 which has as itspair ofoppositely curved surfaces a pair of cylinders one of which is fixed andhas flanges at each end and the other, of which is floating.

4. An apparatus according to claim 1 which has as its pair of oppositelycurved surfaces a pair of cylinders one of which is fixed and hasflangesat each end and one of which is a floating cylinder which isarranged to have restricted movement in a parallel sided recess, one endof which is open and the other end of which is closed, formed in thebody of the apparatus so that when the cylinder is at the open end ofthe recess it abuts the flanges of the fixed cylinder and when it ismoved towards the closed end of the recess by a temporary variation inthe thickness of the web, it acts to restrict air passage to the airchamber so causing an increased air pressure on its surface which forcesit back to the position in which it abuts the flanges of the fixedcylinder.

5. An apparatus according to claim 4- wherein a said pair of cylindersis provided at said outlet passages. V

6. An apparatus for removing liquid from the surface of a wet travellingweb which comprises a chamber through which the web is constrained topass, inlet and outlet passages for the web at least one beingconstituted by the narrow gap between a pair of oppositely curvedsurfaces, the generating lines of which are parallel to the width of theweb, one of the said curved surfaces being fixed and having its endsraised and the other being a floating cylinder which is arranged to havea restricted movement in a parallel sided recess, one end of which isopen and the other end of which is closed and which is formed in thebody of the apparatus, and means for the introduction of air into thesaid chamber at the closed end of the said recess, said air acting tourge the floating cylinder towards the fixed curved surface whereby whenthe floating cylinder is at the open end of the recess it abuts theraised ends of the fixed curved surface such air is enabled to pass intosaid chamber and impinge on both surfaces of the web butwhen thefloating cylinder is displaced away from the position in which is abutsthe raised ends of the fixed curved surfacedue to a variation inthickness of the travelling web the said floating cylinder acts to blockoff the air to the chamber so causing an increased air pressure on itsu'ndersurface which forces it back to the position in which it abuts theraised ends of the fixed curved surface.

7. An apparatus according to claim 6 wherein the fixed curved surfacewith raised ends is a fixed cylinderwit-h flanges on each end.

8. An apparatus according to claim 6 wherein a pair of oppositely curvedsurfaces are located at both the said inlet and outlet passages.

9. An apparatus according to claim 8 wherein said pair of oppositelycurved surfaces consists of a floating cylinder and a fixed cylinderwith flanges at each end.

both the said inlet and l References Cited by the Examiner UNITED STATESPATENTS CHARLES A. WILLMUTH, Primary Examiner, ROBERT w. MICHELL,Examiner.

1. AN APPARATUS FOR REMOVING LIQUID FROM THE SURFACE OF A WET TRAVELLINGWEB WHICH COMPRISES A CHAMBER THROUGH WHICH THE WEB IS CONSTAINED TOPASS, INLET AND OUTLET PASSAGES FOR THE WEB AT LEAST ONE BEINGCONSTITUTED BY THE NARROW GAP BETWEEN A PAIR OF OPPOSITELY CURVEDSURFACES, THE GENERATING LINES OF WHICH ARE PARALLEL TO THE WIDTH OF THEWEB, ONE OF THE SAID SURFACES BEING FIXED AND THE OTHER BEING A SURFACEOF A FLOATING MEMBER WHICH IS SO MOUNTED AS TO ALLOW IT A SMALL DEGREEOF FREEDOM OF MOVEMENT IN A SENSE ALLOWING VARIATION OF THE THICKNESS OFTHE GAP BUT LIMITED IN SUCH MOVEMENT SO THAT GAP CANNOT BE WHOLLY CLOSEDTHEREBY, MEANS FOR INTRODUCING A CURRENT OF AIR INTO SAID CHAMBER SO ASTO URGE SAID FLOATING MEMBER TOWARDS ITS COOPERATING CURVED SURFACE ANDPROVIDING A PATH FOR SUCH AIR TO INPINGE ON BOTH FACES OF THE WEB, ANDMEANS WHEREBY ANY INCREASE IN THE THICKNESS OF THE SAID GAP BEYOND APREDETERMINED VALUE BY REASON OF MOVEMENT OF THE SAID FLOATING MEMBERFROM A PRE-SET POSITION CAUSES AN INCREASE IN THE AIR PRESSURE ON SAIDMEMBER TENDING TO RESTORE IT TO ITS PRE-SET POSITION.